Comparative efficacy and tolerability of pharmacological interventions for attention-deficit/hyperactivity disorder in children, adolescents and adults: protocol for a systematic review and network meta-analysis

Evidence-based prescribing of medications for ADHD: where are we in 2023?

INTRODUCTION

A large number of randomized controlled trials (RCTs) and observational studies on the pharmacotherapy of ADHD are available.

AREAS COVERED

Based on a search in PubMed and PsycInfo (up to 15 September 2022), this review addresses to which extent this body of research is currently able to inform routine prescribing practice, in terms of the choice of medication, titration strategy, augmentation treatments, and use of alternative, non-approved treatments.

EXPERT OPINION

A growing body of evidence is informing prescribers on some, but certainly not all, aspects related to the pharmacological treatment of ADHD in the daily clinical practice, with important weaknesses/gaps that need to be addressed. First, evidence synthesis of RCTs is not able to inform decision-making at the individual patient level. Second, the maximum safe and effective doses, possibly beyond those currently recommended, are not well understood. Third, evidence from RCTs on augmenting strategies is still limited. Fourth, no novel agents with the same or higher effect size of stimulants, in terms of efficacy, but with better tolerability and lower abuse potential, have been found. Implementation of precision psychiatry approaches and stratification of patients in future RCTs will be key to, respectively, individualize the treatment strategies and test etiopathophysiology-based agents.

Comparative cardiovascular side effects of medications for attention-deficit/hyperactivity disorder in children, adolescents and adults: protocol for a systematic review and network meta-analysis

INTRODUCTION

Pharmacotherapy is an important component of the multimodal treatment of attention-deficit/hyperactivity disorder (ADHD). Cardiovascular safety of medications for ADHD is of concern from a clinical and public health standpoint. We aim to conduct a network meta-analysis (NMA) comparing the effects of available medications for ADHD on blood pressure (diastolic and systolic), heart rate and ECG parameters over the short-term and long-term treatment.

METHODS AND ANALYSIS

Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines for protocols and NMAs will be followed. We will include parallel group or cross-over randomised controlled trials (RCTs) conducted in patients with a primary diagnosis of ADHD (no age limits). We will search an extensive number of electronic databases (including MEDLINE, CINAHL, CENTRAL, EMBASE, ERIC, PsycINFO, OpenGrey, Web of Science) from their inception and contact study authors/drug manufacturers to gather relevant unpublished information. No language restrictions will be applied. The main outcomes (assessed at 12 weeks, 26 weeks and 52 weeks) will be: (1) change in diastolic and systolic blood pressure (mm Hg); (2) change in heart rate, measured in beats/min; (3) change in any available ECG parameters. We will conduct random effects of NMA using standardised mean differences with 95% CIs for continuous outcomes and ORs with 95% CIs for dichotomous outcomes. We will use the Cochrane risk of bias tool-version 2 to assess the risk of bias of included RCTs and the Confidence In Network Meta-Analysis tool to evaluate the confidence of evidence contributing to each network estimate. Sensitivity analyses will investigate effects at different dose regimens.

ETHICS AND DISSEMINATION

No institutional review board approval will be necessary. The results of this systematic review and meta-analysis will be presented at national and international conferences and published in peer-reviewed journals.

PROSPERO REGISTRATION NUMBER

CRD42021295352.

New Drugs to Treat ADHD: Opportunities and Challenges in Research and Development

Since the landmark MTA (Multimodal Treatment of ADHD) trial unequivocally demonstrated the efficacy of methylphenidate, catecholaminergic drugs, especially stimulants, have been the therapeutic mainstay in treatment of Attention-Deficit Hyperactivity Disorder (ADHD). We review the new drugs which have entered the ADHD formulary. The lessons learned from drug-candidates that have succeeded in clinical trials together with those that have not have also been considered. What emerges confirms and consolidates the hypothesis that clinically effective ADHD drugs indirectly or directly increase catecholaminergic neurotransmission in the prefrontal cortex (PFC). Attempts to enhance catecholaminergic signalling through modulatory neurotransmitter systems or cognitive-enhancing drugs have all failed. New drugs approved for ADHD are catecholaminergic reuptake inhibitors and releasing agents, or selective noradrenaline reuptake inhibitors. Triple reuptake inhibitors with preferential effects on dopamine have not been successful. The substantial number of failures probably accounts for a continued focus on developing novel catecholaminergic and noradrenergic drugs, and a dearth of drug-candidates with novel mechanisms entering clinical development. However, substantial improvements in ADHD pharmacotherapy have been achieved by the almost exclusive use of once-daily medications and prodrugs, e.g. lisdexamfetamine and Azstarys^®, which improve compliance, deliver greater efficacy and reduce risks for diversion and abuse.

Multimodal Interventions Are More Effective in Improving Core Symptoms in Children With ADHD

Objective: To investigate the effect of sensory integration training combined with EEG biofeedback on core symptoms in children with ADHD. Methods: Fifty-two children with attention-deficit, hyperactive-impulsive and combined ADHD were selected. They were randomly divided into control group, sensory integration training group, EEG biofeedback group, and sensory integration training + EEG biofeedback group, and after 4 months of intervention, concentration time and impulsive- hyperactivity and hyperactivity index scores on the PSQ scale were assessed. Results: Compared with that before the intervention, the attention time was significantly increased (P < 0.01), and the impulsive-hyperactivity and hyperactivity index scores were significantly decreased (P < 0.05, P < 0.01). After the intervention, the attention time was significantly higher than that of the control group (P < 0.05, P < 0.01), the attention time of the multimodal intervention group was significantly higher than that of the single intervention group (P < 0.01), and the impulsive-hyperactivity and hyperactivity index scores were significantly lower than those of the single intervention group (P < 0.05). Conclusion: Multimodal intervention can significantly improve the concentration level of children with ADHD, and significantly improve the behavioral symptoms of impulsive-hyperactivity and hyperactivity. Multimodal interventions were more effective than single interventions in improving core symptoms in children with ADHD. The results of this study provide a reference for related research and practical application.

Review of lisdexamfetamine dimesylate in children and adolescents with attention deficit/hyperactivity disorder

OBJECTIVE

Lisdexamfetamine dimesylate is a stimulant prodrug with low abuse and diversion potential that is used in treatment of attention deficit hyperactivity disorder (ADHD) in children, adolescents and adults. This current literature review article aims to examine safety and efficacy of LDX in children and adolescents for the treatment of ADHD based on currently available data.

METHODS

Relevant English language articles were identified through computerized searches of the MEDLINE database (PubMed and EMBASE) and clinical trials registry up to January 2020 using the following search terms: lisdexamfetamine dimesylate, pro-drug stimulant, attention-deficit and hyperactivity disorders, ADHD, safety, efficacy, children, adolescents, Vyvanse. Forty-two articles were reviewed, 34 of which were included into this review, selected by the limit "clinical trials". This article represents the pharmacological profile, efficacy and safety data of LDX for the treatment of ADHD in children and adolescents.

RESULTS

The collection of studies reviewed identified that LDX was both safe and efficacious in the treatment of ADHD. The most commonly exhibited side effects were appetite suppression, weight loss, headache and insomnia. In comparison to placebo, LDX significantly improved ADHD symptoms and overall quality of life in children and adolescents. In comparison to atomoxetine, LDX showed statistically significant improvements in inattention, impulsivity, and activities of daily living. In comparison to OROS-MPH and placebo, LDX and OROS-MPH showed improvements with the CGI-I score, and ADHD-RS-IV, however, LDX was superior.

CONCLUSION

Patients have seen statistically significant improvements in their ADHD symptomatology in the classroom environment, health related quality of life, and their overall behavior in comparison to placebo, atomoxetine, and OROS-MPH. However, clinical judgment should be utilized when prescribing LDX due to patient specific needs and the side effect profile.

Phase II/III Study of Lisdexamfetamine Dimesylate in Japanese Pediatric Patients with Attention-Deficit/Hyperactivity Disorder

Objective: To further define the efficacy and safety profiles of lisdexamfetamine dimesylate (LDX) in Japanese pediatric patients with attention-deficit/hyperactivity disorder (ADHD). Methods: This was a multicenter, randomized, double-blind, placebo-controlled study of LDX 30, 50, or 70 mg/day for 4 weeks in 76 patients 6-17 years of age with ADHD in Japan. The primary efficacy endpoint was the change in the ADHD Rating Scale-IV (ADHD-RS-IV) total score from baseline to 4 weeks. Secondary efficacy endpoints were: Conners' Third Edition (Japanese version) Parent Rating Scale (Conners 3), Clinical Global Impression-Improvement (CGI-I) scale, and Parent Global Assessment (PGA) scale. Results: Change in the ADHD-RS-IV total score from baseline to 4 weeks was significantly greater (p < 0.0001) in all LDX dosage groups versus placebo (30 mg, -16.38; 50 mg, -18.10; 70 mg, -16.47; placebo, -2.78). At all time points, improvements (decreases) in the ADHD-RS-IV total score were significantly greater in all LDX groups versus placebo. At weeks 3 and 4, improvements from baseline in Conners 3 inattention plus hyperactivity/impulsivity subscale scores were significantly greater (p ≤ 0.0082) for all LDX dosages versus placebo. At week 4, the proportion of LDX-treated patients "much improved" or "very much improved" was 61%-71% on the CGI-I scale (p ≤ 0.0019) and 56%-65% on the PGA scale (p ≤ 0.0170). LDX was generally well tolerated. The most frequent treatment-emergent adverse events (AEs) were decreased appetite, headache, and initial insomnia. No severe/serious AEs occurred, and no AEs specific to Japanese patients were evident. Conclusions: The superiority of LDX 30, 50, and 70 mg/day over placebo was confirmed in Japanese pediatric patients with ADHD, and no major safety or tolerability concerns were identified.

Effects of neurofeedback versus methylphenidate for the treatment of ADHD: systematic review and meta-analysis of head-to-head trials

BACKGROUND

The comparative efficacy and tolerability of methylphenidate (MPH) and neurofeedback (NF) in individuals with attention-deficit/hyperactivity disorder (ADHD) remains uncertain. This study aimed to fill this gap by means of a systematic review/meta-analysis.

METHODS

PubMed, OVID, ERIC, Web of Science, ClinialTrials.gov and a set of Chinese databases were searched until 22 August 2018. Standardised mean differences (SMD) were pooled using comprehensive meta-analysis software.

RESULTS

18 randomised controlled trials (RCTs) were included (778 individuals with ADHD in the NF arm and 757 in the MPH group, respectively; 13 studies in Chinese, five in English). At the study first endpoint, MPH was significantly more efficacious than NF on ADHD core symptoms (ADHD symptoms combined: SMD=-0.578, 95% CI (-1.063 to -0.092)) and on two neuropsychological parameters (inattention:-0.959 (-1.711 to -0.208); inhibition:-0.469 (-0.872 to -0.066)). Dropouts were significantly lower in NF versus MPH (OR=0.412, 0.186 to 0.913). Results were robust to sensitivity analyses, with two important exceptions: removing Chinese studies and non-funded studies, no differences emerged between MPH and NF, although the number of studies was small. At the study follow-up, MPH was superior to NF in some outcomes, but results were inconsistent across raters.

CONCLUSIONS

Due to the risk of bias of included studies, the results of the sensitivity analysis excluding Chinese and non-funded studies, and the mixed findings on at the follow-up endpoint, further high quality studies are needed to assess the comparative efficacy and acceptability of NF and MPH in individuals with ADHD.

TRIAL REGISTRATION NUMBER

CRD42018090256.

A simple formula for enumerating comparisons in trials and network meta-analysis

We present use of a simple formula to calculate the number of pairwise comparisons of interventions within a single trial or network meta-analyses. We used the data from our previous network meta-analysis to build a study-based register and enumerated the direct pairwise comparisons from the trials therein. We then compared this with the number of comparisons predicted by use of the formula and finally with the reported number of comparisons (indirect or direct) within the network meta-analysis. A total of 133 trials of 8 interventions were selected which included 163 comparisons. The network of these showed 16 unique direct comparisons. The formula predicted an expected 28 indirect or direct comparisons and this is the number that were indeed reported. The formula produces an accurate enumeration of the potential comparisons within a single trial or network meta-analysis. Its use could help transparency of reporting should a shortfall occur between comparisons actually used and the potential total.

Systematic review and meta-analysis of the behavioral effects of methylphenidate in the spontaneously hypertensive rat model of attention-deficit/hyperactivity disorder

The spontaneously hypertensive rats (SHR) are the most widely used model for ADHD. While face and construct validity are consolidated, questions remain about the predictive validity of the SHR model. We aim at summarizing the evidence for the predictive validity of SHR by evaluating its ability to respond to methylphenidate (MPH), the most well documented treatment for ADHD. A systematic review was carried out to identify studies evaluating MPH effects on SHR behavior. Studies (n=36) were grouped into locomotion, attention, impulsivity or memory, and a meta-analysis was performed. Meta-regression, sensitivity, heterogeneity, and publication bias analyses were also conducted. MPH increased attentional and mnemonic performances in the SHR model and decreased impulsivity in a dose-dependent manner. However, MPH did not reduce hyperactivity in low and medium doses, while increased locomotor activity in high doses. Thus, since the paradoxical effect of stimulant in reducing hyperactivity was not observed in the SHR model, our study does not fully support the predictive validity of SHR, questioning their validity as an animal model for ADHD.

Meta-Review: Network Meta-Analyses in Child and Adolescent Psychiatry

OBJECTIVE

Network meta-analyses (NMAs) are gaining traction as the preferred method for evidence synthesis of intervention studies. This review aimed to summarize the basics of NMAs and conduct a meta-review of available NMAs on the treatment of child and adolescent psychiatric disorders by appraising their quality.

METHOD

PubMed (Medline), PsycInfo, Embase, Ovid Medline, and Web of Knowledge were systematically searched (last update January 9, 2018). The quality of each included NMA was appraised using the AMSTAR-2 tool and the PRISMA-NMA checklist, which includes specific items for NMAs.

RESULTS

Eighteen NMAs (6 on attention-deficit/hyperactivity disorder; 4 on psychotic disorders; 2 on depression; 2 on anxiety disorders; 1 on obsessive-compulsive disorder; 1 on disruptive behavior disorder, 1 on bipolar disorder, and 1 on antipsychotics across disorders) were retrieved. Results from the AMSTAR-2 assessment showed that only 27% of appraised NMAs were rated as moderate quality; most were rated as low (33%) or critically low (40%) quality. Only 3 of the appraised NMAs reported on all PRISMA-NMA items specific for NMAs; the network structure was graphically presented in most NMAs (80%), and inconsistency was described in only 47%.

CONCLUSION

Given the paucity of head-to-head trials in child and adolescent psychiatry, NMAs have the potential to contribute to the field, because they provide evidence-based hierarchies for treatment decision making, even in the absence of trials directly comparing at least 2 treatments. However, because of important limitations in the included NMAs, additional methodologically sound NMAs are needed to inform future guidelines and clinical practice in child and adolescent psychiatry.

A case series involving young children presenting with accidental ingestion of amphetamine based stimulants

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Attention Deficity Hyperactivity Disorder (ADHD) affects adults and children.

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Stimulant prescribing for ADHD is increasing.

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Overdose of amphetamine based stimulants results in a sympathomimetic toxidrome.

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Lisdexamfetamine dimesylate is the first prodrug stimulant developed to treat ADHD.

Efficacy and safety of drugs for attention deficit hyperactivity disorder in children and adolescents: a network meta-analysis

The aim of this study is to gather evidence of head-to-head double-blind randomized-controlled trials on the efficacy and safety of available treatments for attention deficit hyperactivity disorder (ADHD) in children and adolescents. A systematic review was conducted by two independent reviewers in ten electronic databases (PROSPERO register CRD42016043239). Methodological quality of included studies was evaluated according to the Jadad scale. Network meta-analyses were performed including double-blinded head-to-head trials comparing active allopathic drugs in patients (0-18 years old) diagnosed with ADHD. The results of efficacy and safety of atomoxetine (ATX), bupropion, buspirone (BSP), dexamphetamine, edivoxetine (EDX), guanfacine (GXR), lisdexamfetamine (LDX), methylphenidate (MPH), mixed amphetamine salts, modafinil, pindolol (PDL), reboxetine (RBX), selegiline, and venlafaxine were analyzed using ADDIS software v.1.16.5. Forty-eight trials were identified (n = 4169 participants), of which 12 were used for efficacy analysis and 33 for safety analysis. On the CGI-I scale, the analysis revealed that MPH was more effective than ATX and GXR. For the safety outcomes, according to drug ranks, LDX was more likely to cause sleep disorders (39%) as well as loss of appetite (65%) and behavior problems such as irritability (60%). BSP (71%) and EDX (44%) caused less appetite decrease. For behavioral effects, PDL was considered safest (50%). For any adverse events, RBX (89%) was the safest alternative. The lack of head-to-head trials properly reporting outcomes of interest limited some comparisons. Network meta-analysis offered a broader overview on the available treatments for ADHD, especially for safety issues, and contributes towards evidence gathering and clinical practice decisions. A core outcome set for ADHD should be designed to guide the conduction and report of clinical trials.

Effects of neurofeedback versus methylphenidate for the treatment of attention-deficit/hyperactivity disorder protocol for a systematic review and meta-analysis of head-to-head trials

INTRODUCTION

Attention-deficit/hyperactivity disorder (ADHD) is developmental disorder characterized by inattention and/or hyperactivity/impulsivity. Psychostimulants, including methylphenidate (MPH), are recommended as a first-line pharmacological intervention, whereas neurofeedback (NF) has been proposed as a nonpharmacological option. The comparative effects of MPH and NF need further exploration. We will conduct a systematic review and meta-analysis of head-to-head randomized controlled trials (RCTs) comparing the efficacy and/or tolerability of MPH and NF in children/adolescents and adults with ADHD.

METHOD AND ANALYSIS

We will include published as well as unpublished data. Two investigators will independently search PubMed, OVID, ERIC, Web of Science, ClinialTrials.gov, and a set of Chinese databases, including CNKI, CQVIP, and WanFang for head-to-head RCTs comparing MPH and NF. Experts will be contacted for unpublished data. The primary outcome will be the efficacy on ADHD core symptoms, measured by the change in the severity of ADHD symptoms, from baseline to endpoint and, if available, at follow-up (at any available time point). Secondary outcomes will be: dropouts for any reasons; efficacy on neuropsychological measures (working memory, inattention, and inhibition). We will conduct subgroup analyses to assess the impact of the following variables: age; type of NF; language of publication; comorbidities. Additionally, we will carry out meta-regression analyses to investigate the effect of sponsorship, year of publication, duration of intervention, and age of participants. Sensitivity analyses will be conducted to test the robustness of the findings. Risk of bias of individual studies will be assessed using the Cochrane risk of bias tool. Analyses will be performed using Comprehensive Meta-Analysis Software.

ETHICS AND DISSEMINATION

No ethical issues are foreseen. Results from this study will be published in a peer-reviewed journal and presented at relevant national and international conferences.

TRIALS REGISTRATION NUMBER

PROSPERO CRD42018090256.

Comparative efficacy and tolerability of medications for attention-deficit hyperactivity disorder in children, adolescents, and adults: a systematic review and network meta-analysis

BACKGROUND

The benefits and safety of medications for attention-deficit hyperactivity disorder (ADHD) remain controversial, and guidelines are inconsistent on which medications are preferred across different age groups. We aimed to estimate the comparative efficacy and tolerability of oral medications for ADHD in children, adolescents, and adults.

METHODS

We did a literature search for published and unpublished double-blind randomised controlled trials comparing amphetamines (including lisdexamfetamine), atomoxetine, bupropion, clonidine, guanfacine, methylphenidate, and modafinil with each other or placebo. We systematically contacted study authors and drug manufacturers for additional information. Primary outcomes were efficacy (change in severity of ADHD core symptoms based on teachers' and clinicians' ratings) and tolerability (proportion of patients who dropped out of studies because of side-effects) at timepoints closest to 12 weeks, 26 weeks, and 52 weeks. We estimated summary odds ratios (ORs) and standardised mean differences (SMDs) using pairwise and network meta-analysis with random effects. We assessed the risk of bias of individual studies with the Cochrane risk of bias tool and confidence of estimates with the Grading of Recommendations Assessment, Development, and Evaluation approach for network meta-analyses. This study is registered with PROSPERO, number CRD42014008976.

FINDINGS

133 double-blind randomised controlled trials (81 in children and adolescents, 51 in adults, and one in both) were included. The analysis of efficacy closest to 12 weeks was based on 10 068 children and adolescents and 8131 adults; the analysis of tolerability was based on 11 018 children and adolescents and 5362 adults. The confidence of estimates varied from high or moderate (for some comparisons) to low or very low (for most indirect comparisons). For ADHD core symptoms rated by clinicians in children and adolescents closest to 12 weeks, all included drugs were superior to placebo (eg, SMD -1·02, 95% CI -1·19 to -0·85 for amphetamines, -0·78, -0·93 to -0·62 for methylphenidate, -0·56, -0·66 to -0·45 for atomoxetine). By contrast, for available comparisons based on teachers' ratings, only methylphenidate (SMD -0·82, 95% CI -1·16 to -0·48) and modafinil (-0·76, -1·15 to -0·37) were more efficacious than placebo. In adults (clinicians' ratings), amphetamines (SMD -0·79, 95% CI -0·99 to -0·58), methylphenidate (-0·49, -0·64 to -0·35), bupropion (-0·46, -0·85 to -0·07), and atomoxetine (-0·45, -0·58 to -0·32), but not modafinil (0·16, -0·28 to 0·59), were better than placebo. With respect to tolerability, amphetamines were inferior to placebo in both children and adolescents (odds ratio [OR] 2·30, 95% CI 1·36-3·89) and adults (3·26, 1·54-6·92); guanfacine was inferior to placebo in children and adolescents only (2·64, 1·20-5·81); and atomoxetine (2·33, 1·28-4·25), methylphenidate (2·39, 1·40-4·08), and modafinil (4·01, 1·42-11·33) were less well tolerated than placebo in adults only. In head-to-head comparisons, only differences in efficacy (clinicians' ratings) were found, favouring amphetamines over modafinil, atomoxetine, and methylphenidate in both children and adolescents (SMDs -0·46 to -0·24) and adults (-0·94 to -0·29). We did not find sufficient data for the 26-week and 52-week timepoints.

INTERPRETATION

Our findings represent the most comprehensive available evidence base to inform patients, families, clinicians, guideline developers, and policymakers on the choice of ADHD medications across age groups. Taking into account both efficacy and safety, evidence from this meta-analysis supports methylphenidate in children and adolescents, and amphetamines in adults, as preferred first-choice medications for the short-term treatment of ADHD. New research should be funded urgently to assess long-term effects of these drugs.

FUNDING

Stichting Eunethydis (European Network for Hyperkinetic Disorders), and the UK National Institute for Health Research Oxford Health Biomedical Research Centre.

Are the effects of methylphenidate uncertain?

OBJECTIVES

A recent systematic review and meta-analysis of randomised controlled trials of methylphenidate (MPH) in children and adolescents by a Cochrane group, led by Storebø, raised concern around the level of evidence supporting the use of this medication for attention-deficit/hyperactivity disorder (ADHD) in children and adolescents. This led to several critical responses from a number of ADHD experts.

METHODS

This paper reviews the conclusions reached from the Storebø meta-analysis by a critical analysis of methodologies used along with drawing on extant literature.

RESULTS

The controversy raised by the Cochrane meta-analysis should lead to a balanced reflection on the research priorities and needs for the field.

CONCLUSIONS

It is hoped the controversy will ultimately lead to improve the quality of the research on the efficacy, effectiveness and tolerability of MPH for ADHD.

Risk of Bias and Quality of Evidence for Treatment of ADHD With Stimulant Medication

Storebø et al. provide a concise summary of two Cochrane reviews about benefits and harms of treatment of attention-deficit/hyperactivity disorder (ADHD) with methylphenidate: (1) a review of 185 randomized controlled trials that estimated benefits (e.g., moderate-to-large reduction in teacher-rated ADHD symptoms) and (2) a review of 260 nonrandomized trials that estimated harms (e.g., infrequent serious but frequent nonserious adverse events). They also mention (without providing much detail) additional information from the structured Cochrane method about the risk for bias in the trials reviewed (assessed as being high) and quality of evidence of the outcomes considered (rated as being very low). This led to the conclusion that "the jury is still out on benefits and harms." A similar conclusion of the first review generated an extensive debate in the literature. Some details will be summarized and discussed herein to provide context in case the recent review and the summary by Storebø et al. revive the debate.

Meditation-based therapies for attention-deficit/hyperactivity disorder in children, adolescents and adults: a systematic review and meta-analysis

BACKGROUND

The efficacy of meditation-based therapies for attention deficit/hyperactivity disorder (ADHD) across the lifespan remains uncertain.

OBJECTIVE

To conduct a systematic review and meta-analysis of randomised controlled trials (RCTs) assessing the efficacy of meditation-based therapies for ADHD core symptoms and associated neuropsychological dysfunctions in children/adolescents or adults with ADHD.

METHODS

We searched Pubmed, PsycInfo, Embase+Embase Classic, Ovid Medline and Web of Knowledge with no language, date or type of document restriction, up to 5 May 2018. Random-effects model was used. Heterogeneity was assessed with Cochran's Q and I2 statistics. Publication (small studies) bias was assessed with funnel plots and the Egger's test. Studies were evaluated with the Cochrane risk of bias (RoB) tool. Analyses were conducted using Comprehensive Meta-Analysis.

FINDINGS

13 RCTs (seven in children/adolescents, n=270 and six in adults, n=339) were retained. Only one RCT was double-blind.Meditation-based therapies were significantly more efficacious than the control conditions in decreasing the severity of ADHD core symptoms (inattention+hyperactivity/impulsivity: children/adolescents: Hedge's g=-0.44, 95% CI -0.69 to -0.19, I20%; adults: Hedge's g=-0.66, 95% CI -1.21 to -0.11, I281.81%). No significant effects were found on neuropsychological measures of inattention and inhibition in children/adolescents. In adults, significant effects were detected on working memory and inhibition, although these results were based on a small number of studies (n=3). 57% and 43% of the studies in children/adolescents were rated at overall unclear and high risk of bias, respectively. In adults, 33% and 67% of the studies were deemed at overall unclear and high risk of bias, respectively. No evidence of publication bias was found.

CONCLUSIONS

Despite statistically significant effects on ADHD combined core symptoms, due to paucity of RCTs, heterogeneity across studies and lack of studies at low risk of bias, there is insufficient methodologically sound evidence to support meditation-based therapies for ADHD.

TRIAL REGISTRATION NUMBER

PROSPERO 2018 [CRD42018096156].

The pharmacology of amphetamine and methylphenidate: Relevance to the neurobiology of attention-deficit/hyperactivity disorder and other psychiatric comorbidities

Psychostimulants, including amphetamines and methylphenidate, are first-line pharmacotherapies for individuals with attention-deficit/hyperactivity disorder (ADHD). This review aims to educate physicians regarding differences in pharmacology and mechanisms of action between amphetamine and methylphenidate, thus enhancing physician understanding of psychostimulants and their use in managing individuals with ADHD who may have comorbid psychiatric conditions. A systematic literature review of PubMed was conducted in April 2017, focusing on cellular- and brain system-level effects of amphetamine and methylphenidate. The primary pharmacologic effect of both amphetamine and methylphenidate is to increase central dopamine and norepinephrine activity, which impacts executive and attentional function. Amphetamine actions include dopamine and norepinephrine transporter inhibition, vesicular monoamine transporter 2 (VMAT-2) inhibition, and monoamine oxidase activity inhibition. Methylphenidate actions include dopamine and norepinephrine transporter inhibition, agonist activity at the serotonin type 1A receptor, and redistribution of the VMAT-2. There is also evidence for interactions with glutamate and opioid systems. Clinical implications of these actions in individuals with ADHD with comorbid depression, anxiety, substance use disorder, and sleep disturbances are discussed.